4,510 research outputs found
Late-successional and old-growth forests in the northeastern United States: Structure, dynamics, and prospects for restoration.
Abstract
Restoration of old-growth forest structure is an emerging silvicultural goal, especially in those regions where old-growth abundance falls below the historic range of variability. However, longitudinal studies of old-growth dynamics that can inform silvicultural and policy options are few. We analyzed the change in structure, including stand density, diameter distribution, and the abundance of large live, standing dead, and downed dead trees on 58 late-successional and old-growth plots in Maine, USA, and compared these to regional data from the U.S. Forest Inventory and Analysis program. Structural dynamics on the late-successional plots reflected orderly change associated with density-dependent growth and mortality, but dynamics on the old-growth plots were more variable. Some plots experienced heavy mortality associated with beech bark disease. Diameter distributions conformed poorly to a classic exponential distribution, and did not converge toward such a distribution at the plot scale. Although large live trees showed a broad trend of increasing density in regional forests, recent harvesting patterns offset a considerable fraction of those gains, while mean diameter was static and the number of large dead trees was weakly declining. Even though forests of the northeast are aging, changes in silviculture and forest policy are necessary to accelerate restoration of old-growth structure
From the Shores of Tripoli to the Deserts of Iraq: Congress and the President in Offensive and Defensive Wars (Winner of American Constitution Society\u27s National Student Writing Competition)
The On-Sale Bar to Patentability: Actual Reduction to Practice Not Required in Pfaff v. Wells Electronics, Inc.
A patent grants to an inventor the exclusive right to prevent others from making, using, or selling his invention throughout the United States. However, an inventor is statutorily barred from receiving a patent for an invention that was “on sale” prior to one year before his U.S. filing date. An offer to sell cannot bar patentability until an invention exists. The general issue in applying the “on sale” bar is “[a]t what point is the invention sufficiently developed such that, coupled with an offer to sell, the inventor’s commercial activities invoke the on sale bar?” The United States Supreme Court’s decision in Pfaff v. Wells Electronics, Inc. once again affirmed that reduction to practice is not necessary to trigger this one year period (known as the “critical date”). This decision has serious effects for both sole inventors and big companies. This Note will discuss the background of the “on sale” bar to patentability and the particular facts of Pfaff v. Wells Electronics, Inc., and will analyze why the Supreme Court decided that the “on sale” bar does not require an actual reduction to practice of the invention
Pinpoint Redistricting and the Minimization of Partisan Gerrymandering
For over twenty years, the political gerrymandering claim under the Equal Protection Clause of the Fourteenth Amendment has been mired in ambiguity because the Supreme Court and lower courts have failed to come up with a clear standard to determine whether a redistricting plan is unconstitutional. In 2006, however, a new phenomenon that this Comment terms Âżpinpoint redistrictingÂż was used by GeorgiaÂżs Republican-dominated state legislature to alter the boundaries of a small group of districts rather than all of the stateÂżs district boundaries, severely weakening the strength of Democratic voters in the affected districts. The pinpoint redistricting changed the affected districts from competitive to strongly Republican, and as a result, the redistricting partyÂżs candidates achieved sizable victories in the 2006 elections
The Effect of Winding Curvature and Core Permeability on the Power Losses and Leakage Inductance of High-Frequency Transformers
At the frequencies used in switching dc-dc converters, the skin and proximity effects have a significant effect on both the losses and leakage inductance of the transformers used in these circuits. Analytical expressions that have been derived to calculate ac resistance and leakage inductance have primarily used a 1-D approximation. They also have used Cartesian coordinates or approximations that are equivalent to Cartesian coordinates, as well as usually assuming an ideal core of infinite permeability. The classical result in the case of the resistance/losses is Dowell’s equation, and there are analogous results for leakage inductance. This dissertation derives new equations that take the effect of winding curvature into account by using cylindrical coordinates. These equations are also more general in that they permit any interleaving pattern as well as variable layer thicknesses and gaps between layers. Additionally, new equations for the magnetic field coefficients are derived that take the core permeability into account, which requires a full 2-D model and the method of images applied in two dimensions. These coefficients then allow calculations of resistance/losses and leakage inductance that also take the core permeability and winding width into account. The accuracy of all of these equations is assessed by comparing their results with those of finite-element analysis (FEA) simulations. Due to the large number of parameters involved with the fully general equations, a statistical approach is used in which a large number of randomly generated devices are simulated. Finally, for a special class of more specific transformers, the effects of a reduced number of independent parameters on the resistance/losses and leakage inductance is determined empirically. The relative sensitivity of these quantities on these parameters is also determined
The Geography Of Metaphors: Traveling, Learning, And The Writing Process
Vicki SherbertWriting takes practice, much like any other activity in life. Usually, I’m more than willing to jump into any opportunity to write, letting my thoughts fall onto the page. The whole idea for my honors project, originally, centered on curating a collection of different examples of writing to use in my future secondary English classroom. Spoiler alert: that didn’t end up happening because life had other plans. What my honors project has become is an exercise in reflective writing. I adopted an informal tone, as I wanted my writing to reflect my thoughts as they occur in my head; what is on the page is no one’s voice but my own, as imperfect as it may be. Through my reflection, I have tried to synthesize my experience during my semester abroad by interspersing writing I produced while I was living in Ireland with writing from the months following my return to the States. Ultimately, I wanted my honors project to be an exploration into my psyche and what I have learned that will continue to affect me as I go through life, not an excuse for a wayward project gone awry. With that in mind, here it is: my qualitative dive into introspection
Comet nongravitational forces and meteoritic impacts
We have considered those comets whose original orbits have been determined to be hyperbolic when only planetary perturbations are accounted for. It is found that formally unbound incident trajectories correlate most confidently with orbits that have small perihelion distances and move in a retrograde sense relative to planetary motion. Arguments are presented that these results are not due to measurement error or to selection effects. We conclude that the phenomenon is attributable to enhanced volatility leading to abnormally large nongravitational forces. Since the effect is absent in the prograde small-perihelia population, increased insolation is not the sole explanation. It is suggested that the significance of the retrograde correlation is connected with a larger energy of relative motion between retrograde comets and a population of prograde ecliptic meteoroids which impact the comet mantle exposing the underlying volatiles. The subsequent enhanced outgassing is the cause of the larger nongravitational forces
London or New York? Implications of Enron Debacle for Law and Accounting Reform in Hong Kong
The collapse of the American corporation Enron has profound and hard lessons for Hong Kong. Enron has provided new examples of ways in which it is possible for unethical business behaviour to be lawful, in the positivist sense of law. This article argues that the complex relationship between the Companies Ordinance and the protection of investors can never be stated as more than a set of principles. The superstructure of the 'public interest' rests, somewhat uneasily, on the professional shoulders of accountants. Accounting standards fill the gap between law and ethics in the system. The meaning of what is understood by a 'true and fair view' remains the same, whilst the 'contents' (ie specific accounting regulations) can be expected to change. A question for Hong Kong is who decides, and who should have the final say on those 'contents': the accounting profession, the stock exchange, an accounting standard setter, the Securities and Futures Commission, or the Government?published_or_final_versio
Effect of sampling rate and record length on the determination of stability and control derivatives
Flight data from five aircraft were used to assess the effects of sampling rate and record length reductions on estimates of stability and control derivatives produced by a maximum likelihood estimation method. Derivatives could be extracted from flight data with the maximum likelihood estimation method even if there were considerable reductions in sampling rate and/or record length. Small amplitude pulse maneuvers showed greater degradation of the derivative maneuvers than large amplitude pulse maneuvers when these reductions were made. Reducing the sampling rate was found to be more desirable than reducing the record length as a method of lessening the total computation time required without greatly degrading the quantity of the estimates
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